Sally, we hardly knew you. Sally ride lived a life in the spotlight as America's first woman to go to space. Now two years after her death comes a new book spilling some surprising secrets. Liftoff of sts 7 and America's first woman astronaut. There was so much she kept hidden during all those years in the spotlight. It sure is fun. Sally ride was the exuberant young physicist who in 1983 became the country any first female in space. I'm going to drink chocolate milk running on the treadmill. And spent decades inspiring girls. During all that time there was a huge part of her life that was secret only to be revealed in a single line in her obituary two years ago. I think probably the thing most people were surprised to learn about sally was the fact that she had been living with another woman for 27 years. Why was she so insistent on privacy on this score? There was no question in my mind, but that if sally ride had been openly gay and if she had applied to nasa, number one she never would have been selected as an astronaut. Number two never would have flown, and number three, never would have been first American woman in space. If she hadn't been private she wouldn't have made history. If she hadn't been private, she wouldn't have made history. Lynn Sherr first met sally ride covering the shuttle program. Lynn Sherr, ABC news, Florida. We hit it off immediately. Reporter: She has written a new biography on ride which reveals many secrets including the fact amidst the hoopla of her first shuttle ride. The thing I will remember most about that flight, it was fun. And the most fun in my life. With her face on magazine covers, sally ride felt the need to see a shrink. I didn't realize the psychic price she paid for her fame. This was a woman who was genetically an introvert. She really was quite shy. She sacrificed a lot to be the public figure that we wanted her to be. Notwithstanding her shyness, behind the scenes, ride was capable of bold action. The new book reveals that on a trip to the eastern bloc at the height of the cold war, she defied strict orders from the state department and had a secret meeting with a Russian female cosmonaut. Sally had purposely worn that night under her blouse a t-shirt that she had worn on orbit during the sds 7 flight and said to her I would look to give you this. The investigation into the challenger explosion, she was handed a key document showing that nasa had knowledge of the faulty equipment believed to have led to the disaster. She wanted the troouth how to get out and wanted to protect her source as well. So she quitely leaked it. This was a smart, brave, at times, sly, calculating woman? She was a great diplomat. She would have been an extraordinary, senator, congresswoman, president, you name it. Sally ride died two years ago at age 61 from cancer. What do you conclude based on all these surprising things you learned about her in the course of writing the book? She was the person that I thought she was. But she was much more. She had so much more to her. There were so many deeper layers that she chose not to let too many of us know about. A remarkable woman. Lynn Sherr's new book called "Sally ride, Now, a paid presentation

This transcript has been automatically generated and may not be 100% accurate.

Astronaut Sally Ride's Secret Journey

New book chronicles the life of the first woman in space and her decision not to come out as a gay astronaut.

Astronaut Sally Ride Dies of Pancreatic Cancer

The space pioneer battled cancer for 17 months.

Sally Ride, First U.S. Woman in Space, Dies

America's original female astronaut remembered as a trailblazer.

Space Pioneer Sally Ride Dies at 61

First American woman in space lost her battle with pancreatic cancer.

{"id":23984401,"title":"The Secrets of Sally Ride","duration":"3:36","description":"Author reveals intimate details about the life of America's first woman in space.","section":"Nightline","mediaType":"Default"}